Such a hydraulic steering is known, for example, from DE 10 2006 010 695 B4. Vehicles equipped with such a hydraulic steering can either be steered via the hydraulic steering valve in an automatic mode or they can be steered via the manual steering section, for example using steering means like a steering wheel.
When the vehicle is controlled via the hydraulic steering valve, the steering is performed automatically, for example by a control unit using the global positioning system (GPS). Such a functionality is, for example, important for agricultural vehicles.
The operator or driver of the vehicle is basically free to use the steering valve section or the manual steering section. To this end, a selection valve can be used with which the user can choose the appropriate mode of operation. However, for safety reasons it is important that the driver can also use the manual steering section to steer the wheels, for example, in emergency situations.
To this end, in DE 10 2006 010 695 B1 a steering wheel sensor is provided that can detect if the steering wheel has been turned by the driver.
However, the usage of a sensor on the steering wheel has the disadvantage that such a sensor is not always reliable and increases the costs of installation and maintenance of the hydraulic steering.